Laurentia (also known as the North American craton), like all craton land, was created as continents moved about the surface of the Earth, bumping into other continents and drifting away. A craton ( Greek kratos / κρἀτος ( neut. "strength" is an old and stable part of the Continental crust that has survived A continent is one of several large Landmasses on Earth. They are generally identified by Convention rather than any strict criteria with seven regions EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001
Many times in its past, Laurentia has been a separate continent as it is now in the form of North America. A continent is one of several large Landmasses on Earth. They are generally identified by Convention rather than any strict criteria with seven regions During other times in its past, Laurentia has been part of a supercontinent. In Geology, a supercontinent is a Landmass comprising more than one Continental core or Craton. It is named after the Laurentian Shield, which in turn is named after the St. Lawrence River. The Canadian Shield &mdash also called the Laurentian Plateau, or Bouclier Canadien (French &mdash is a large geological shield covered by Saint Lawrence River (in French: fleuve Saint-Laurent; Kahnawáˀkye in Tuscarora, Kaniatarowanenneh meaning big waterway
Laurentia owes its existence to a network of Early Proterozoic orogenic belts. The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and Small microcontinents and oceanic islands collided with the ever-growing Laurentia, and together formed the stable Archean craton we see today. For a topic outline on this subject see List of basic Australia topics.
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Interior platform
In eastern and central Canada, much of the stable craton is exposed at the surface as the Canadian Shield. The Canadian Shield &mdash also called the Laurentian Plateau, or Bouclier Canadien (French &mdash is a large geological shield covered by In the United States the craton bedrock is covered with sedimentary rocks of the interior platform except in northern Minnesota and Wisconsin and the Upper Peninsula of Michigan. The United States of America —commonly referred to as the The sequence of rocks varies from approximately 1,000 to in excess of 6,100 metres (3,500–20,000 ft) in thickness. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International A foot (plural feet or foot; symbol or abbreviation ft or sometimes &prime – the prime symbol) is a non-SI unit The cratonic rocks are metamorphic and igneous while the overlying sedimentary rocks are composed mostly of limestones, sandstones, and shales. Metamorphic rock is the result of the transformation of an existing rock type the protolith, in a process called Metamorphism, which means "change Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Sandstone is a Sedimentary rock composed mainly of Sand -size Mineral or rock grains. Shale (also called mudstone) is a fine-grained Sedimentary rock whose original constituents were Clay minerals or Muds It is characterized by These sedimentary rocks were deposited from 650 to 290 million years ago.
Tectonic setting
The metamorphic and igneous rocks of the "basement complex" were created 1. In Geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover or more generally 5 to 1. 0 billion years ago in a tectonically active setting. It was a setting of great pressure and temperature. The younger sedimentary rocks that were deposited on top of this basement complex were formed in a setting of quiet marine and river waters. During much of Mississippian time, the craton was the site of an extensive marine carbonate platform on which mainly limestones and some dolostones and evaporites were deposited. This platform extended either from the present Appalachian Mountains or Mississippi Valley to the present Great Basin. The craton was covered by shallow, warm, tropical epicontinental or epicratonic sea (meaning literally "on the craton") that had maximum depths of only about 60 metres (200 ft) at the shelf edge. Sometimes land masses or mountain chains rose up on the distant edges of the craton and then eroded down, shedding their sand across the landscape. A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak
Geological history of Laurentian craton in chronological order
- ~2. 5 billion years ago, Arctica formed as an independent continent. Arctica was an ancient Continent which formed approximately 2
- ~2. 45 billion years ago, Arctica was part of the major supercontinent Kenorland. Kenorland was one of the earliest Supercontinents on Earth It is believed to have formed during the Neoarchaean Era ~2
- ~2. 1 billion years ago, when Kenorland shattered, the Arctican craton was part of the minor supercontinent Nena along with Baltica and Eastern Antarctica. Nena was an ancient Supercontinent that consisted of the Cratons of Arctica, Baltica, and East Antarctica. Baltica redirects here For the Russian beer, see Baltika Breweries Baltica is a name applied by geologists to a late- Proterozoic, The East Antarctic craton is an ancient Craton that forms most of Antarctica.
- ~1. 8 billion years ago, Laurentia was part of the major supercontinent Columbia. Columbia is the name of one of the Earth's oldest Supercontinents It was first proposed by J
- ~1. 5 billion years ago, Laurentia was an independent continent.
- ~1. 1 billion years ago, Laurentia was part of the major supercontinent Rodinia. For the Genus of Metalmark butterflies, see Rodinia (butterfly.
- ~750 million years ago, Laurentia was part of the minor supercontinent Protolaurasia. Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic Laurentia nearly rifted apart.
- ~600 million years ago, Laurentia was part of the major supercontinent Pannotia. Pannotia, first described by Ian W D Dalziel in 1997 is a hypothetical Supercontinent that existed from the Pan-African orogeny about 600 million years ago to the
- ~Cambrian, Laurentia was an independent continent. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with
- ~Ordovician, Laurentia was shrinking and Baltica got bigger. The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488
- ~Devonian, Laurentia collided against Baltica, forming the minor supercontinent Euramerica. The Devonian is a geologic period and system of the Paleozoic era spanning from to million years ago. Euramerica (also known as Laurussia or Old Red Continent) was a minor Supercontinent created in the Devonian as the result of a collision between
- ~Permian, all major continents collide against each other for forming the major supercontinent Pangaea. The Permian is a geologic period and system that extends from 299 Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in
- ~Jurassic, Pangaea rifted into two minor supercontinents: Laurasia and Gondwana. The Jurassic is a geologic period and system that extends from about Ma (million years ago to Ma that is from the end of the Triassic to the beginning Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago Laurentia was part of the minor supercontinent Laurasia.
- ~Cretaceous, Laurentia was an independent continent called North America. The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of
- ~Neogene, Laurentia, in the form of North America, crashed into South America, forming the minor supercontinent America. The Neogene is a geologic period and system starting 2303 ± 0 South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a
- ~250 million years from now, all continents may crash together, forming the major supercontinent Pangaea Ultima. Pangaea Ultima (also Pangaea Proxima, Neopangaea, or Pangaea II) is a possible future Supercontinent configuration and an alternative to the Laurentia will be part of Pangaea Ultima.
Other use
- "Laurentia" was also a proposed name for the country that united as Canada. The name of Canada has been in use since the earliest European settlement in Canada, with the Name originating from a First Nations word Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page
- There is a Saint Laurentia (see Palatia and Laurentia). Palatia and Laurentia (Sante Palazia e Laurenzia Lorenza were virgin Martyrs of Ancona, venerated as Saints by the Catholic Church.
External links
- Paleogeography of the Southwestern US - Paleogeographic history of southwestern Laurentia, goes back to 1. 7 billion years ago.
- Mesozoic Paleogeography and Tectonic History, Western North America - Paleogeographic history of western Laurentia, goes back to the Permian period.
- USGS Interior Plains Region web site
- The Dynamic Earth, United Plates of America from The Smithsonian National Museum of Natural History
External image
- Map of Laurentia - A map of Laurentia
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